A gas turbine engine generally includes a fan and a core arranged in flow communication with one another. Additionally, the core of the gas turbine engine general includes, in serial flow order, a compressor section, a combustion section, a turbine section, and an exhaust section. In operation, air is provided from the fan to an inlet of the compressor section where one or more axial compressors progressively compress the air until it reaches the combustion section. Fuel is mixed with the compressed air and burned within the combustion section to provide combustion gases. The combustion gases are routed from the combustion section to the turbine section. The flow of combustion gasses through the combustion section drives the combustion section and is then routed through the exhaust section, e.g., to atmosphere. In particular configurations, the turbine section is mechanically coupled to the compressor section by a shaft extending along an axial direction of the gas turbine engine.
During operation, lubrication is provided to various components of the core engine and/or fan to increase a longevity of such components and remove heat from such components. The lubrication is collected in various sumps. For example, certain gas turbine engines include one or more forward engine sumps positioned inward of a main air flowpath of the core engine and one or more aft engine sumps also positioned inward of the main air flowpath. Scavenge pumps, located outward of the main air flowpath, are included to pump lubrication from the sumps into a tank.
An air pressure surrounding the sumps is maintained relatively high to decrease a likelihood of lubrication leaking from such sumps and posing a potential risk to the engine. For example, compressed air from the compressor section can be introduced to a void surrounding the sumps. Additionally, at least certain gas turbine engines include an eductor for lowering an internal pressure of the sumps by bleeding airflow from the main air flowpath of the core engine into an axial centerline. The airflow bled from the main air flowpath generates an airflow through, and negative pressure within, the axial centerline. The sumps may be in airflow communication through an air-oil separator with the axial centerline, such that at least some air in the sumps is urged into the axial centerline, while centrifuging the oil to sump endwalls for scavenging while lowering a pressure within the sumps.
However, such configuration can be inefficient and/or ineffective. For example, an eductor may not be capable of reducing a pressure within the axial centerline by a desired amount, thus requiring the void surrounding the sumps to be maintained at a relatively high pressure and temperature. Additionally, such a configuration can reduce an amount of thrust of the gas turbine engine by bleeding air from the main air flowpath. Accordingly, a gas turbine engine having one or more features for reducing a pressure in one or more sumps positioned inward of a main air flowpath would be useful.